Push-button structures which include a fixed structure portion and an operation body attached to the fixed structure portion so as to be able to protrude and retract with respect to the fixed structure portion have been known. The operation body is provided with a sliding portion configured to be slidable with respect to the fixed structure portion, and an operation head connected to the outside of the sliding portion and having a larger diameter than the sliding portion to overhang the sliding portion.
For example, in Patent Document 1, an elastic member which has a cylindrical shape surrounding the sliding portion and which is capable of being elastically deformed is held between the overhang portion of the operation head and the fixed structure portion. The elastic member has a first contact portion that is in contact with the inner surface of the overhang portion of the operation head, a second contact portion that is in contact with a portion of the fixed structure portion which faces the overhang portion, and a third contact portion that is in contact with the sliding portion.